Heavy duty pneumatic radial tires with organic fiber cord bead reinforcing layer

Abstract

A tire wherein one or more rubberized organic fiber cord layers extending over an end of a carcass turnup portion in a radial direction of the tire are arranged so as to extend from a position near to an outside of the bead core over the end of the turnup portion toward the outside of the tire and spread apart to the turnup portion. A tire wherein one or more rubberized organic fiber cord layers are arranged so as to extend from a position exceeding over an end of a bead portion reinforcing layer made of a steel cord layer toward the outside of the tire extending over the end of the turnup portion in the radial direction of the tire and spread apart to the reinforcing layer. And also, a tire wherein a cord layer portion of one or more rubberized organic fiber cord layers extending over the end of the turnup portion in the radial direction of the tire and outside the turnup portion has a first bent portion bending toward the inside of the tire.

What is claimed is:  
     
       1. A heavy duty pneumatic radial tire comprising; a carcass of at least one rubberized cord ply of radial arrangement toroidally extending between a pair of bead cores embedded in bead portions and wound around the bead core from inside of the tire toward outside to form a turnup portion, at least one rubberized organic fiber cord layer extending outside the turnup portion over an end of the turnup portion outward in a radial direction of the tire, in which the at least one organic fiber cord layer is arranged so as to extend from a position near to an outside of the bead core over the end of the turnup portion toward the outside of the tire and spread apart from the turnup portion, and wherein the at least one organic fiber cord layer has a first bent portion acutely bending toward the outside of the tire with respect to a winding direction of the turnup portion extending outward from the position near to the outside of the bead core in the radial direction, and a bending angle (α) of the first bent portion with respect to the winding direction of the turnup portion at a radial section of the tire is within a range of 15-60°. 
     
     
       2. A tire according to claim  1 , wherein a bead portion reinforcing layer made of a rubberized steel cord layer is disposed between the turnup portion of the carcass and the at least one organic fiber cord layer and an outer end of the reinforcing layer in the radial direction of the tire is located inward from the end of the turnup portion in the radial direction of the tire. 
     
     
       3. A tire according to claim  1 , wherein an end of the first bent portion of the at least one organic fiber cord layer is an outermost end in the radial direction of the tire. 
     
     
       4. A tire according to claim  1 , wherein the at least one organic fiber cord layer has the first bent portion and a second bent portion again bending from an end of the first bent portion toward an inside of the tire, and an inclination angle (β) of the second bent portion inclined with respect to the winding direction of the turnup portion is within a range of 15-60° at the radial section of the tire. 
     
     
       5. A tire according to claim  4 , wherein the at least one organic fiber cord layer has the first bent portion, the second bent portion and a third bent portion extending outward from an end of the second bent portion at an approximately equal distance to an outer surface of the tire in the radial direction of the tire. 
     
     
       6. A tire according to claim  1 , wherein the at least one organic fiber cord layer has the first bent portion and a third bent portion extending outward from an end of the first bent portion at approximately an equal distance to an outer surface of the tire in the radial direction of the tire. 
     
     
       7. A tire according to claim  6 , wherein the at least one organic fiber cord layer has the first bent portion, the third bent portion and a fourth bent portion extending from the third bent portion toward the inside of the tire and acutely inclining with respect to the winding direction of the turnup portion. 
     
     
       8. A tire according to claim  7 , wherein an inclination angle (γ) of the fourth bent portion with respect to the winding direction of the turnup portion is within a range of 15-60° at the section of the tire.